A lifetime of research in creep, superplasticity, and ultrafine‐grained materials
A lifetime of research in creep, superplasticity, and ultrafine‐grained materials
A long‐term career at the University of Southern California, followed by an appointment at the University of Southampton, provided an opportunity to conduct extensive research into the flow behavior of polycrystalline metals. Initially, research is conducted on creep properties at elevated temperatures and it is shown that solid solution metallic alloys exhibit transitions in creep behavior with dislocation climb and viscous glide as the dominant rate‐controlling mechanisms. There are transitions between climb and glide with increasing stress and also a breakaway from the glide process at high stresses. These transitions are predicted theoretically and the results are in excellent agreement with the experimental data for a wide range of alloys. Attention is directed to the process of superplasticity and it is shown that the flow occurs by grain boundary sliding with accommodation by a limited amount of intragranular slip. Separate rate equations are developed for sliding in coarse‐grained materials and in superplastic materials where the grain sizes are generally <10 μm so that flow occurs without the development of any subgrains. Finally, attention is directed to the properties of ultrafine‐grained materials having submicrometer or nanometer grain sizes produced through the application of severe plastic deformation.
creep, flow mechanisms, grain boundary sliding, superplasicity, ultrafine grained materials
1-8
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
23 August 2019
Langdon, Terence G.
86e69b4f-e16d-4830-bf8a-5a9c11f0de86
Langdon, Terence G.
(2019)
A lifetime of research in creep, superplasticity, and ultrafine‐grained materials.
Advanced Engineering Materials, , [1900442].
(doi:10.1002/adem.201900442).
Abstract
A long‐term career at the University of Southern California, followed by an appointment at the University of Southampton, provided an opportunity to conduct extensive research into the flow behavior of polycrystalline metals. Initially, research is conducted on creep properties at elevated temperatures and it is shown that solid solution metallic alloys exhibit transitions in creep behavior with dislocation climb and viscous glide as the dominant rate‐controlling mechanisms. There are transitions between climb and glide with increasing stress and also a breakaway from the glide process at high stresses. These transitions are predicted theoretically and the results are in excellent agreement with the experimental data for a wide range of alloys. Attention is directed to the process of superplasticity and it is shown that the flow occurs by grain boundary sliding with accommodation by a limited amount of intragranular slip. Separate rate equations are developed for sliding in coarse‐grained materials and in superplastic materials where the grain sizes are generally <10 μm so that flow occurs without the development of any subgrains. Finally, attention is directed to the properties of ultrafine‐grained materials having submicrometer or nanometer grain sizes produced through the application of severe plastic deformation.
Text
Langdon-AEM-Invited-final
- Accepted Manuscript
More information
Accepted/In Press date: 25 June 2019
e-pub ahead of print date: 12 July 2019
Published date: 23 August 2019
Keywords:
creep, flow mechanisms, grain boundary sliding, superplasicity, ultrafine grained materials
Identifiers
Local EPrints ID: 435039
URI: http://eprints.soton.ac.uk/id/eprint/435039
ISSN: 1438-1656
PURE UUID: 1ac3c7b5-6f85-44c4-bc95-d85aeb630717
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Date deposited: 18 Oct 2019 16:30
Last modified: 17 Mar 2024 02:55
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